 // 获取导航栏高度
 export function getNavBarHeight() {
  const systemInfo = uni.getSystemInfoSync()
  const statusBarHeight = systemInfo.statusBarHeight 
  const navigationBarHeight = systemInfo.platform === 'android' ? 48 : 44 // 根据不同平台设置导航栏高度 
  const totalHeight = statusBarHeight + navigationBarHeight 
  return totalHeight
}
// 获取自定义导航返回按钮top值
export function getCustomBackItemTop(size) {
  const systemInfo = uni.getSystemInfoSync()
  const statusBarHeight = systemInfo.statusBarHeight 
  const navigationBarHeight = systemInfo.platform === 'android' ? 48 : 44 // 根据不同平台设置导航栏高度 
  const backBtnTop = statusBarHeight + (navigationBarHeight - size)/2  
  return backBtnTop
}